Beyond the boundaries of established science an avalanche of exotic ideas compete for our attention. Experts tell us that these ideas should not be permitted to take up the time of working scientists, and for the most part they are surely correct. But what about the gems in the rubble pile? By what ground-rules might we bring extraordinary new possibilities to light?

-We know little about Earth's core structure and composition, and studying it is a tricky task.-Canberra researchers re-analysed earthquake data and calculated that the inner core is softer than previously thought.-This means the core might contain pockets of melted material, or it might be a property of iron under high pressure and temperature.

... To probe the core, scientists analyse how S and P waves bounce around and through the planet.

For decades, seismologists have sought signs of S waves in the inner core.

Their speed can tell you about the stiffness, or rigidity, of the material.

And even though S waves can't travel through the liquid outer core, they do exist in the solid inner core.

This is because when a P wave travelling through the outer core hits the inner core, some of its energy is converted to S waves.

Those S waves can propagate through the inner core until they hit the liquid outer core, where they're converted again to P waves.

... It turned out that S waves were around 2.5 per cent slower than previously thought. And because S waves move fastest through stiffer material, it follows that the inner core is softer than previously thought, too.

Although 2.5% doesn't sound like much, the variation is in the same ball park as the variation in wave velocity between spreading centers and continental regions. The image below shows s wave anomalies at 100 km. Here the velocities vary up 10% either way from the norm for that depth.

Oct 26, 2018, 12:19 PMI am, you are, we are American. Picture: Getty ImagesMonash University team investigate “unusual” rocks on Tasmania’s NW coastResearch finds match with rocks from the Grand Canyon in the USAConfirms both land masses were part of the same supercontinent more than 700 million years agoA part of the north-west coast of Tasmania is the Grand Canyon’s long-lost cousin.

A paper recently published in the journal Geology by geologists at Monash University followed a hunch about these rocks:

Picture: Peter Farquhar/Business InsiderThey’re part of a very famous bit of land, Rocky Cape National Park, where cave middens reveal evidence of Aboriginal occupation from at least 8000 years ago. It’s been officially recognised as “pinmatik” (“peen mah teek”) since 1991.

But hundreds of millions of years ago, it was part of a megacontinent known as Rodinia, and joined to what is now known as the west coast of the USA, 13,000km away.

In particular, it’s got bits of the Grand Canyon in it, and that makes it very, very interesting for earth science researchers.

Rodinia was formed when an even older supercontinent known as Columbia broke apart, but you won’t find any Rodinian fossils at Rocky Cape, because Rodinia existed one billion years ago, well before terrestrial life had formed.

It began breaking up around 700 million years ago.

Picture: Peter Farquhar/Business InsiderThe discovery was made by Jack Mulder, a research fellow at Monash University in Melbourne, who thought the rocks looked similar to those in the Grand Canyon, and decided to test his theory.

The hunch turned out to be on the money. Rocks from both regions shared similar stratigraphy, depositional age, and they contain matching hafnium isotopes readings.

Mulder was able to trace where the ancient sand and mud came from by analysing the geochemical fingerprint of tiny grains of the mineral zir-con, which makes up a small proportion of the sedimentary rocks.

“When we compared the Tasmanian rocks to similar-aged rocks nearby in Australia, we found that not only did they look very different, but they also had distinct zircon fingerprints. Instead, the enigmatic Tasmanian rocks look strikingly similar to the one billion year old sedimentary rocks found near the bottom of Grand Canyon in Arizona,” he says.

“In addition to forming at the same time and in similar geological environment, the ancient sedimentary rocks in Tasmania and Grand Canyon share the same zircon fingerprint. Together, this evidence supports the interpretation that these now widely separated rock units once formed part of the same sedimentary basin.”

That dates pinmatik back as much as 1.1 billion years to the late Mesoproterozoic era.

One such professor, Alan Collins, at the University of Adelaide, Australia, told New Scientist the paper shows Tasmania “holds the key” to understanding how the planet was put together.

It could help future geologists build full plate models of ancient Earth, he said.

A 1.5-kilometer asteroid, intact or in pieces, may have smashed into an ice sheet just 13,000 years ago.NASA SCIENTIFIC VISUALIZATION STUDIOOn a bright July day 2 years ago, Kurt Kjær was in a helicopter flying over northwest Greenland—an expanse of ice, sheer white and sparkling. Soon, his target came into view: Hiawatha Glacier, a slow-moving sheet of ice more than a kilometer thick. It advances on the Arctic Ocean not in a straight wall, but in a conspicuous semicircle, as though spilling out of a basin. Kjær, a geologist at the Natural History Museum of Denmark in Copenhagen, suspected the glacier was hiding an explosive secret. The helicopter landed near the surging river that drains the glacier, sweeping out rocks from beneath it. Kjær had 18 hours to find the mineral crystals that would confirm his suspicions.

What he brought home clinched the case for a grand discovery. Hidden beneath Hiawatha is a 31-kilometer-wide impact crater, big enough to swallow Washington, D.C., Kjær and 21 co-authors report today in a paper in Science Advances. The crater was left when an iron asteroid 1.5 kilometers across slammed into Earth, possibly within the past 100,000 years.

Though not as cataclysmic as the dinosaur-killing Chicxulub impact, which carved out a 200-kilometer-wide crater in Mexico about 66 million years ago, the Hiawatha impactor, too, may have left an imprint on the planet's history. The timing is still up for debate, but some researchers on the discovery team believe the asteroid struck at a crucial moment: roughly 13,000 years ago, just as the world was thawing from the last ice age. That would mean it crashed into Earth when mammoths and other megafauna were in decline and people were spreading across North America.

The impact would have been a spectacle for anyone within 500 kilometers. A white fireball four times larger and three times brighter than the sun would have streaked across the sky. If the object struck an ice sheet, it would have tunneled through to the bedrock, vaporizing water and stone alike in a flash. The resulting explosion packed the energy of 700 1-megaton nuclear bombs, and even an observer hundreds of kilometers away would have experienced a buffeting shock wave, a monstrous thunder-clap, and hurricane-force winds. Later, rock debris might have rained down on North America and Europe, and the released steam, a greenhouse gas, could have locally warmed Greenland, melting even more ice.

The news of the impact discovery has reawakened an old debate among scientists who study ancient climate. A massive impact on the ice sheet would have sent meltwater pouring into the Atlantic Ocean—potentially disrupting the conveyor belt of ocean currents and causing temperatures to plunge, especially in the Northern Hemisphere. "What would it mean for species or life at the time? It's a huge open question," says Jennifer Marlon, a paleoclimatologist at Yale University.

A decade ago, a small group of scientists proposed a similar scenario. They were trying to explain a cooling event, more than 1000 years long, called the Younger Dryas, which began 12,800 years ago, as the last ice age was ending. Their controversial solution was to invoke an extraterrestrial agent: the impact of one or more comets. The researchers proposed that besides changing the plumbing of the North Atlantic, the impact also ignited wildfires across two continents that led to the extinction of large mammals and the disappearance of the mammoth-hunting Clovis people of North America. The research group marshaled suggestive but inconclusive evidence, and few other scientists were convinced. But the idea caught the public's imagination despite an obvious limitation: No one could find an impact crater.

Proponents of a Younger Dryas impact now feel vindicated. "I'd unequivocally predict that this crater is the same age as the Younger Dryas," says James Kennett, a marine geologist at the University of California, Santa Barbara, one of the idea's original boosters.

But Jay Melosh, an impact crater expert at Purdue University in West Lafayette, Indiana, doubts the strike was so recent. Statistically, impacts the size of Hiawatha occur only every few million years, he says, and so the chance of one just 13,000 years ago is small. No matter who is right, the discovery will give ammunition to Younger Dryas impact theorists—and will turn the Hiawatha impactor into another type of projectile. "This is a hot potato," Melosh tells Science. "You're aware you're going to set off a firestorm?"

It started with a hole. In 2015, Kjær and a colleague were studying a new map of the hidden contours under Greenland's ice. Based on variations in the ice's depth and surface flow patterns, the map offered a coarse suggestion of the bedrock topography—including the hint of a hole under Hiawatha.

Kjær recalled a massive iron meteorite in his museum's courtyard, near where he parks his bicycle. Called Agpalilik, Inuit for "the Man," the 20-ton rock is a fragment of an even larger meteorite, the Cape York, found in pieces on northwest Greenland by Western explorers but long used by Inuit people as a source of iron for harpoon tips and tools. Kjær wondered whether the meteorite might be a remnant of an impactor that dug the circular feature under Hiawatha. But he still wasn't confident that it was an impact crater. He needed to see it more clearly with radar, which can penetrate ice and reflect off bedrock.

Kjær's team began to work with Joseph MacGregor, a glaciologist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, who dug up archival radar data. MacGregor found that NASA aircraft often flew over the site on their way to survey Arctic sea ice, and the instruments were sometimes turned on, in test mode, on the way out. "That was pretty glorious," MacGregor says.

The radar pictures more clearly showed what looked like the rim of a crater, but they were still too fuzzy in the middle. Many features on Earth's surface, such as volcanic calderas, can masquerade as circles. But only impact craters contain central peaks and peak rings, which form at the center of a newborn crater when—like the splash of a stone in a pond—molten rock rebounds just after a strike. To look for those features, the researchers needed a dedicated radar mission.

Coincidentally, the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, had just purchased a next-generation ice-penetrating radar to mount across the wings and body of their Basler aircraft, a twin-propeller retrofitted DC-3 that's a workhorse of Arctic science. But they also needed financing and a base close to Hiawatha.

Kjær took care of the money. Traditional funding agencies would be too slow, or prone to leaking their idea, he thought. So he petitioned Copenhagen's Carlsberg Foundation, which uses profits from its global beer sales to finance science. MacGregor, for his part, enlisted NASA colleagues to persuade the U.S. military to let them work out of Thule Air Base, a Cold War outpost on northern Greenland, where German members of the team had been trying to get permission to work for 20 years. "I had retired, very serious German scientists sending me happy-face emojis," MacGregor says.

NASA and German aircraft used radar to see the contours of an impact crater beneath the ice of Hiawatha Glacier.JOHN SONNTAG/NASAThree flights, in May 2016, added 1600 kilometers of fresh data from dozens of transits across the ice—and evidence that Kjær, MacGregor, and their team were onto something. The radar revealed five prominent bumps in the crater's center, indicating a central peak rising some 50 meters high. And in a sign of a recent impact, the crater bottom is exceptionally jagged. If the asteroid had struck earlier than 100,000 years ago, when the area was ice free, erosion from melting ice farther inland would have scoured the crater smooth, MacGregor says. The radar signals also showed that the deep layers of ice were jumbled up—another sign of a recent impact. The oddly disturbed patterns, MacGregor says, suggest "the ice sheet hasn't equilibrated with the presence of this impact crater."

But the team wanted direct evidence to overcome the skepticism they knew would greet a claim for a massive young crater, one that seemed to defy the odds of how often large impacts happen. And that's why Kjær found himself, on that bright July day in 2016, frenetically sampling rocks all along the crescent of terrain encircling Hiawatha's face. His most crucial stop was in the middle of the semicircle, near the river, where he collected sediments that appeared to have come from the glacier's interior. It was hectic, he says—"one of those days when you just check your samples, fall on the bed, and don't rise for some time."

In that outwash, Kjær's team closed its case. Sifting through the sand, Adam Garde, a geologist at the Geological Survey of Denmark and Greenland in Copenhagen, found glass grains forged at temperatures higher than a volcanic eruption can generate. More important, he discovered shocked crystals of quartz. The crystals contained a distinctive banded pattern that can be formed only in the intense pressures of extraterrestrial impacts or nuclear weapons. The quartz makes the case, Melosh says. "It looks pretty good. All the evidence is pretty compelling."

Now, the team needs to figure out exactly when the collision occurred and how it affected the planet.

The Younger Dryas, named after a small white and yellow arctic flower that flourished during the cold snap, has long fascinated scientists. Until human-driven global warming set in, that period reigned as one of the sharpest recent swings in temperature on Earth. As the last ice age waned, about 12,800 years ago, temperatures in parts of the Northern Hemisphere plunged by as much as 8°C, all the way back to ice age readings. They stayed that way for more than 1000 years, turning advancing forest back into tundra.

The trigger could have been a disruption in the conveyor belt of ocean currents, including the Gulf Stream that carries heat northward from the tropics. In a 1989 paper in Nature, Kennett, along with Wallace Broecker, a climate scientist at Columbia University's Lamont-Doherty Earth Observatory, and others, laid out how meltwater from retreating ice sheets could have shut down the conveyor. As warm water from the tropics travels north at the surface, it cools while evaporation makes it saltier. Both factors boost the water's density until it sinks into the abyss, helping to drive the conveyor. Adding a pulse of less-dense freshwater could hit the brakes. Paleoclimate researchers have largely endorsed the idea, although evidence for such a flood has been lacking until recently.

Then, in 2007, Kennett suggested a new trigger. He teamed up with scientists led by Richard Firestone, a physicist at Lawrence Berkeley National Laboratory in California, who proposed a comet strike at the key moment. Exploding over the ice sheet covering North America, the comet or comets would have tossed light-blocking dust into the sky, cooling the region. Farther south, fiery projectiles would have set forests alight, producing soot that deepened the gloom and the cooling. The impact also could have destabilized ice and unleashed meltwater that would have disrupted the Atlantic circulation.

The climate chaos, the team suggested, could explain why the Clovis settlements emptied and the megafauna vanished soon afterward. But the evidence was scanty. Firestone and his colleagues flagged thin sediment layers at dozens of archaeological sites in North America. Those sediments seemed to contain geochemical traces of an extraterrestrial impact, such as a peak in iridium, the exotic element that helped cement the case for a Chicxulub impact. The layers also yielded tiny beads of glass and iron—possible meteoritic debris—and heavy loads of soot and charcoal, indicating fires.

The team met immediate criticism. The decline of mammoths, giant sloths, and other species had started well before the Younger Dryas. In addition, no sign existed of a human die-off in North America, archaeologists said. The nomadic Clovis people wouldn't have stayed long in any site. The distinctive spear points that marked their presence probably vanished not because the people died out, but rather because those weapons were no longer useful once the mammoths waned, says Vance Holliday, an archaeologist at The University of Arizona in Tucson. The impact hypothesis was trying to solve problems that didn't need solving.

The geochemical evidence also began to erode. Outside scientists could not detect the iridium spike in the group's samples. The beads were real, but they were abundant across many geological times, and soot and charcoal did not seem to spike at the time of the Younger Dryas. "They listed all these things that aren't quite sufficient," says Stein Jacobsen, a geochemist at Harvard University who studies craters.

Yet the impact hypothesis never quite died. Its proponents continued to study the putative debris layer at other sites in Europe and the Middle East. They also reported finding microscopic diamonds at different sites that, they say, could have been formed only by an impact. (Outside researchers question the claims of diamonds.)

Now, with the discovery of Hiawatha crater, "I think we have the smoking gun," says Wendy Wolbach, a geochemist at De-Paul University in Chicago, Illinois, who has done work on fires during the era.

The impact would have melted 1500 gigatons of ice, the team estimates—about as much ice as Antarctica has lost because of global warming in the past decade. The local greenhouse effect from the released steam and the residual heat in the crater rock would have added more melt. Much of that freshwater could have ended up in the nearby Labrador Sea, a primary site pumping the Atlantic Ocean's overturning circulation. "That potentially could perturb the circulation," says Sophia Hines, a marine paleoclimatologist at Lamont-Doherty.

Leery of the earlier controversy, Kjær won't endorse that scenario. "I'm not putting myself in front of that bandwagon," he says. But in drafts of the paper, he admits, the team explicitly called out a possible connection between the Hiawatha impact and the Younger Dryas.

Banded patterns in the mineral quartz are diagnostic of shock waves from an extraterrestrial impact.ADAM GARDE, GEUSThe evidence starts with the ice. In the radar images, grit from distant volcanic eruptions makes some of the boundaries between seasonal layers stand out as bright reflections. Those bright layers can be matched to the same layers of grit in cataloged, dated ice cores from other parts of Greenland. Using that technique, Kjær's team found that most ice in Hiawatha is perfectly layered through the past 11,700 years. But in the older, disturbed ice below, the bright reflections disappear. Tracing the deep layers, the team matched the jumble with debris-rich surface ice on Hiawatha's edge that was previously dated to 12,800 years ago. "It was pretty self-consistent that the ice flow was heavily disturbed at or prior to the Younger Dryas," MacGregor says.

Other lines of evidence also suggest Hiawatha could be the Younger Dryas impact. In 2013, Jacobsen examined an ice core from the center of Greenland, 1000 kilometers away. He was expecting to put the Younger Dryas impact theory to rest by showing that, 12,800 years ago, levels of metals that asteroid impacts tend to spread did not spike. Instead, he found a peak in platinum, similar to ones measured in samples from the crater site. "That suggests a connection to the Younger Dryas right there," Jacobsen says.

For Broecker, the coincidences add up. He had first been intrigued by the Firestone paper, but quickly joined the ranks of naysayers. Advocates of the Younger Dryas impact pinned too much on it, he says: the fires, the extinction of the megafauna, the abandonment of the Clovis sites. "They put a bad shine on it." But the platinum peak Jacobsen found, followed by the discovery of Hiawatha, has made him believe again. "It's got to be the same thing," he says.

Yet no one can be sure of the timing. The disturbed layers could reflect nothing more than normal stresses deep in the ice sheet. "We know all too well that older ice can be lost by shearing or melting at the base," says Jeff Severinghaus, a paleoclimatologist at the Scripps Institution of Oceanography in San Diego, California. Richard Alley, a glaciologist at Pennsylvania State University in University Park, believes the impact is much older than 100,000 years and that a subglacial lake can explain the odd textures near the base of the ice. "The ice flow over growing and shrinking lakes interacting with rough topography might have produced fairly complex structures," Alley says.

A recent impact should also have left its mark in the half-dozen deep ice cores drilled at other sites on Greenland, which document the 100,000 years of the current ice sheet's history. Yet none exhibits the thin layer of rubble that a Hiawatha-size strike should have kicked up. "You really ought to see something," Severinghaus says.

Brandon Johnson, a planetary scientist at Brown University, isn't so sure. After seeing a draft of the study, Johnson, who models impacts on icy moons such as Europa and Enceladus, used his code to recreate an asteroid impact on a thick ice sheet. An impact digs a crater with a central peak like the one seen at Hiawatha, he found, but the ice suppresses the spread of rocky debris. "Initial results are that it goes a lot less far," Johnson says.

In 2016, Kurt Kjær looked for evidence of an impact in sand washed out from underneath Hiawatha Glacier. He would find glassy beads and shocked crystals of quartz.SVEND FUNDEREven if the asteroid struck at the right moment, it might not have unleashed all the disasters envisioned by proponents of the Younger Dryas impact. "It's too small and too far away to kill off the Pleistocene mammals in the continental United States," Melosh says. And how a strike could spark flames in such a cold, barren region is hard to see. "I can't imagine how something like this impact in this location could have caused massive fires in North America," Marlon says.

It might not even have triggered the Younger Dryas. Ocean sediment cores show no trace of a surge of freshwater into the Labrador Sea from Greenland, says Lloyd Keigwin, a paleoclimatologist at the Woods Hole Oceanographic Institution in Massachusetts. The best recent evidence, he adds, suggests a flood into the Arctic Ocean through western Canada instead.

An external trigger may be unnecessary in any case, Alley says. During the last ice age, the North Atlantic saw 25 other cooling spells, probably triggered by disruptions to the Atlantic's overturning circulation. None of those spells, known as Dansgaard-Oeschger (D-O) events, was as severe as the Younger Dryas, but their frequency suggests an internal cycle played a role in the Younger Dryas, too. Even Broecker agrees that the impact was not the ultimate cause of the cooling. If D-O events represent abrupt transitions between two regular states of the ocean, he says, "you could say the ocean was approaching instability and somehow this event knocked it over."

Still, Hiawatha's full story will come down to its age. Even an exposed impact crater can be a challenge for dating, which requires capturing the moment when the impact altered existing rocks—not the original age of the impactor or its target. Kjær's team has been trying. They fired lasers at the glassy spherules to release argon for dating, but the samples were too contaminated. The researchers are inspecting a blue crystal of the mineral apatite for lines left by the decay of uranium, but it's a long shot. The team also found traces of carbon in other samples, which might someday yield a date, Kjær says. But the ultimate answer may require drilling through the ice to the crater floor, to rock that melted in the impact, resetting its radioactive clock. With large enough samples, researchers should be able to pin down Hiawatha's age.

Given the remote location, a drilling expedition to the hole at the top of the world would be costly. But an understanding of recent climate history—and what a giant impact can do to the planet—is at stake. "Somebody's got to go drill in there," Keigwin says. "That's all there is to it."

PARIS (Reuters) - It may not change how you buy bananas, but scientists have voted to redefine the value of a kilogram, in what they called a landmark decision that will boost the accuracy of scientific measurements.

A replica of the International Prototype Kilogram is pictured is seen at the 26th meeting of the General Conference on Weights and Measures (CGPM) to vote on the redefinition of four base units of the International System of Units (SI) in Versailles, France, November 16, 2018. REUTERS/Benoit Tessier

Since 1889, a kilogram has been defined by a shiny lump of platinum-iridium kept in a special glass case and known as the International Prototype of the Kilogram. It is housed at the headquarters of the International Bureau of Weights and Measures (whose French acronym is BIPM), just outside Paris.

Members of the BIPM, which groups some 60 nations, agreed on Friday after a week-long meeting at the nearby Palace of Versailles to redefine a kilogram in terms of a tiny but unchanging value called the “Planck constant”.

They also voted to update definitions for the ampere (electrical current), the kelvin (thermodynamic temperature) and the mole (amount of a substance).

All modern mass measurements are derived from the kilogram, whether micrograms of pharmaceutical medicine or gold dust, kilos of fruit or fish, or tonnes of steel.

The problem is the prototype doesn’t always weigh the same. Even inside its three glass bell jars it picks up microparticles of dirt and is affected by the atmosphere. Sometimes it needs cleaning, which can affect its mass.

That can have profound implications. If the prototype were to lose mass, atoms would in theory weigh more since the base kilogram must by definition always weigh a kilogram.

Scientists have been trying for decades to define a constant value for the kilogram that is derived from immutable physics, in the same way they have done for other standard units (SI units) overseen by the BIPM.

For example, a meter isn’t 100 centimeters, it’s actually “the length of the path traveled by light in a vacuum during a time interval of 1/299,792,458 of a second”.

The “Planck constant”, which derives from quantum physics, can be used along with a Kibble balance, an exquisitely accurate weighing machine, to calculate the mass of an object using a precisely measured electromagnetic force.

“The SI redefinition is a landmark moment in scientific progress,” said Martin Milton, director of the BIPM.

“Using the fundamental constants we observe in nature as a foundation for important concepts such as mass and time means that we have a stable foundation from which to advance our scientific understanding, develop new technologies and address some of society’s greatest challenges.”

Barry Inglis, who heads the committee for weights and measures, said the implications were immense.

“We will now no longer be bound by the limitations of objects in our measurement of the world, but have universally accessible units that can pave the way to even greater accuracy, and even accelerate scientific advancement,” he said.

It is arguably the most significant redefinition of an SI unit since the second was recalculated in 1967, a decision that helped ease communication across the world via technologies like GPS and the internet.

The new definitions agreed by the BIPM will come into force on May 20, 2019.

The “Planck constant”, which derives from quantum physics, can be used along with a Kibble balance, an exquisitely accurate weighing machine, to calculate the mass of an object using a precisely measured electromagnetic force.

“The SI redefinition is a landmark moment in scientific progress,” said Martin Milton, director of the BIPM.

Useful heuristic devices for sure, but 'Planck constants' are not constants, they (SI) are all derived units and the article is full of puffery.The Planck Ratio, of energy (Ev's) over time (s) appears constant, at least locally.

The rest of SI is also derived, eventually down to a basic unit of charge and that unit itself de-rived from pure observation. Only a so-called "natural unit" as a kind of push to pull ratio.

Instruments picked up the seismic waves more than 10,000 miles away—but bizarrely, nobody felt them.

Photograph by Camille SeamanNovember 28, 2018On the morning of November 11, just before 9:30 UT, a mysterious rumble rolled around the world.

The seismic waves began roughly 15 miles off the shores of Mayotte, a French island sandwiched between Africa and the northern tip of Madagascar. The waves buzzed across Africa, ringing sensors in Zambia, Kenya, and Ethiopia. They traversed vast oceans, humming across Chile, New Zealand, Canada, and even Hawaii nearly 11,000 miles away.

These waves didn't just zip by; they rang for more than 20 minutes. And yet, it seems, no human felt them.

Only one person noticed the odd signal on the U.S. Geological Survey's real-time seismogram displays. An earthquake enthusiast who uses the handle @matarikipax saw the curious zigzags and posted images of them to Twitter. That small action kicked off another ripple of sorts, as researchers around the world attempted to suss out the source of the waves. Was it a meteor strike? A submarine volcano eruption? An ancient sea monster rising from the deep?

“I don't think I've seen anything like it,” says Göran Ekström, a seismologist at Columbia University who specializes in unusual earthquakes.

“It doesn't mean that, in the end, the cause of them is that exotic,” he notes. Yet many features of the waves are remarkably weird—from their surprisingly monotone, low-frequency “ring” to their global spread. And researchers are still chasing down the geologic conundrum.

Why are the low-frequency waves so weird?

In a normal earthquake, the built-up tensions in Earth's crust release with a jolt in mere seconds. This sends out a series of waves known as a “wave train” that radiates from the point of the rupture, explains Stephen Hicks, a seismologist at the University of Southampton.

The fastest-traveling signals are Primary waves, or P-waves, which are compression waves that move in bunches, like what happens to an extended slinky that gets suddenly pushed at one end. Next come the secondary waves, or S-waves, which have more of a side-to-side motion. Both of these so-called body waves have relatively high frequencies, Hicks says, “a sort of ping rather than a rumbling.”

Earthquakes 101 Earthquakes are unpredictable and can strike with enough force to bring buildings down. Find out what causes earthquakes, why they're so deadly, and what's being done to help buildings sustain their hits. Finally, chugging along at the end come slow, long-period surface waves, which are similar to the strange signals that rolled out from Mayotte. For intense earthquakes, these surface waves can zip around the planet multiple times, ringing Earth like a bell, Hicks says.

However, there was no big earthquake kicking off the recent slow waves. Adding to the weirdness, Mayotte's mystery waves are what scientists call monochromatic. Most earthquakes send out waves with a slew of different frequencies, but Mayotte's signal was a clean zigzag dominated by one type of wave that took a steady 17 seconds to repeat.

“It's like you have colored glasses and [are] just seeing red or something,” says Anthony Lomax, an independent seismology consultant.

Mayotte's volcanic roots

Based on the scientific sleuthing done so far, the tremors seem to be related to a seismic swarm that's gripped Mayotte since last May. Hundreds of quakes have rattled the small nation during that time, most radiating from around 31 miles offshore, just east of the odd ringing. The majority were minor trembles, but the largest clocked in at magnitude 5.8 on May 15, the mightiest in the island's recorded history. Yet the frequency of these shakes has declined in recent months—and no traditional quakes rumbled there when the mystery waves began on November 11.

The French Geological Survey (BRGM) is closely monitoring the recent shaking, and it suggests that a new center of volcanic activity may be developing off the coast. Mayotte was formed from volcanism, but its geologic beasts haven't erupted in over 4,000 years. Instead, BRGM's analysis suggests that this new activity may point to magmatic movement offshore—miles from the coast under thousands of feet of water. Though this is good news for the island inhabitants, it's irksome for geologists, since it's an area that hasn't been studied in detail.

“The location of the swarm is on the edge of the [geological] maps we have,” says Nicolas Taillefer, head of the seismic and volcanic risk unit at BRGM. “There are a lot things we don't know.” And as for the November 11 mystery wave, he says, “it's something quite new in the signals on our stations.”

Motion in the ocean

Since mid-July, GPS stations on the island have tracked it sliding more than 2.4 inches to the east and 1.2 inches to the south, according data from Institut National de L’information Géographique et Forestière. Using these measurements, Pierre Briole of the Ecole Normale Supérieure in Paris estimated that a magma body that measures about a third of a cubic mile is squishing its way through the subsurface near Mayotte.

The early period of rumbling was also overprinted with what seemed to be the P- and S- waves of tiny tremors, explains Lomax, who spotted the faint pings by filtering out the low-frequency signals. Such pings are commonly associated with magma moving and fracturing rock as it squirts through the crust. But even those signals were a little strange, says Helen Robinson, a Ph.D. candidate in applied volcanology at the University of Glasgow.

“They're too nice; they're too perfect to be nature,” she jokes, although she quickly adds that an industrial source is impossible, since no wind farms or drilling are taking place in the deep waters off Mayotte's shores.

Ekström thinks that the events on the morning of November 11 actually did begin with an earthquake of sorts equivalent to a magnitude 5 temblor. It passed by largely unnoticed, he suggests, because it was what's known as a slow earthquake. These quakes are quieter than their speedy cousins since they come from a gradual release of stress that can stretch over minutes, hours, or even days.

“The same deformation happens, but it doesn't happen as a jolt,” Ekström says.

These slow types of quakes are often associated with volcanic activity. At the Mount Nyiragongo volcano in the Democratic Republic of Congo, a similar slow earthquake and low-frequency waves were linked with a magma chamber collapsing. Slow quakes were also stunningly frequent during the most recent fiery run of Kilauea in Hawaii, which produced nearly 60 of these events between May and the end of July, sending seismic waves around the world.

Assembling the geologic puzzle

So what is actually causing the super-slow vibrations at Mayotte? A submarine eruption could produce these low rumblings, but evidence for such an event has yet to materialize.

Most current guesses revolve around resonance in a magma chamber, triggered by some type of subsurface shift or chamber collapse. The resonance itself can be any type of rhythmic motion, like sloshing of the molten rock, or a pressure wave ricocheting through the magma body, Ekström explains. Studying the intricate features of the seismic waves could yield clues to the size and shape of the molten material lurking below.

It is very difficult, really, to say what the cause is and whether anyone's theories are correct.Helen Robinson, University of Glasgow

“It's like a music instrument,” says Jean-Paul Ampuero, a seismologist at the Université Côte d'Azur in France. “The notes of a music instrument—whether it's grave or very pitchy—depends on the size of the instrument.”

The signal's odd uniformity could be due, in part, to the surrounding rocks and sediments, Lomax adds. Perhaps the local geology is filtering the sounds and only letting this single 17-second wave period escape.

Robinson agrees with this idea, noting that the geology here is extremely complex. Mayotte sits in a region crisscrossed by ancient faults—including fracture zones from the final breakup of the southern supercontinent Gondwana. What's more, the underlying crust is somewhat transitional, shifting between the thick continental crusts and the thinner oceanic crusts. Perhaps this complexity drives the simplicity of the escaping waves, Robinson says.

Secrets of the sea

For now, though, the lack of data makes it tough to say more about the wiggly forms. Hicks' preliminary models hinted that the waves emanated from subsurface inflation, rather than a magma chamber draining or collapsing. But with a little additional data, the model flipped and pointed to chamber deflation instead.

It also could be a bit of both, notes Robinson: “Some collapse mechanisms, you can get inflation and deflation occurring at the same time,” she says. Or sometimes they can alternate, pumping up and down like Earth's fiery lungs.

“It is very difficult, really, to say what the cause is and whether anyone's theories are correct—whether even what I'm saying has any relevance to the outcome of what's going on,” Robinson says.

BRGM plans to do ocean bottom surveys to get more detailed information about the region and investigate the possibility of a submarine eruption. In the meantime, the seismic sleuthing continues with the data that's available. Whether the cause is ordinary or extraordinary remains to be seen, Lomax says, but the science—and the fun—is in the chase.

“Depending on what field and what time in history, 99.9 percent of the time, it's ordinary, or noise, or a mistake, and 0.1 percent, it's something” he says. “But that's just the way it goes. That's the way it should go. That's scientific advance.”

Editor's Note: This story has been updated to clarify the source of the data and analysis on Mayotte's geological movement and subsurface magma body size.

... scientists ... today reported several ... discoveries, including how much and what kinds of life exist in the deep subsurface under the greatest extremes of pressure, temperature, and low nutrient availability.

... they have approximated the size of the deep biosphere—2 to 2.3 billion cubic km (almost twice the volume of all oceans) - as well as the carbon mass of deep life: 15 to 23 billion tonnes (an average of at least 7.5 tonnes of carbon per cu km subsurface).

... "Exploring the deep subsurface is akin to exploring the Amazon rainforest. There is life everywhere, and everywhere there's an awe-inspiring abundance of unexpected and unusual organisms. ... " ... says Mitch Sogin

... Among the many remaining enigmas of deep life on Earth:

Movement: How does deep life spread—laterally through cracks in rocks? Up, down? How can deep life be so similar in South Africa and Seattle, Washington? Did they have similar origins and were separated by plate tectonics, for example? Or do the communities themselves move? What roles do big geological events (such as plate tectonics, earthquakes; creation of large igneous provinces; meteoritic bombardments) play in deep life movements?

Origins: Did life start deep in Earth (either within the crust, near hydrothermal vents, or in subduction zones) then migrate up, toward the sun? Or did life start in a warm little surface pond and migrate down? How do subsurface microbial zombies reproduce, or live without dividing for millions to tens of millions of years?

Energy: Is methane, hydrogen, or natural radiation (from uranium and other elements) the most important energy source for deep life? Which sources of deep energy are most important in different settings? How do the absence of nutrients, and extreme temperatures and pressure, impact microbial distribution and diversity in the subsurface?

Study shows the Sahara swung between lush and desert conditions every 20,000 years, in sync with monsoon activityA new analysis of African dust reveals the Sahara swung between green and desert conditions every 20,000 years, in sync with changes in the Earth’s tilt. Credit: Massachusetts Institute of TechnologyThe Sahara desert is one of the harshest, most inhospitable places on the planet, covering much of North Africa in some 3.6 million square miles of rock and windswept dunes. But it wasn't always so desolate and parched. Primitive rock paintings and fossils excavated from the region suggest that the Sahara was once a relatively verdant oasis, where human settlements and a diversity of plants and animals thrived.

Now researchers at MIT have analyzed dust deposited off the coast of west Africa over the last 240,000 years, and found that the Sahara, and North Africa in general, has swung between wet and dry climates every 20,000 years. They say that this climatic pendulum is mainly driven by changes to the Earth's axis as the planet orbits the sun, which in turn affect the distribution of sunlight between seasons—every 20,000 years, the Earth swings from more sunlight in summer to less, and back again.

For North Africa, it is likely that, when the Earth is tilted to receive maximum summer sunlight with each orbit around the sun, this increased solar flux intensifies the region's monsoon activity, which in turn makes for a wetter, "greener" Sahara. When the planet's axis swings toward an angle that reduces the amount of incoming summer sunlight, monsoon activity weakens, producing a drier climate similar to what we see today.

"Our results suggest the story of North African climate is dominantly this 20,000-year beat, going back and forth between a green and dry Sahara," says David McGee, an associate professor in MIT's Department of Earth, Atmospheric and Planetary Sciences. "We feel this is a useful time series to examine in order to understand the history of the Sahara desert and what times could have been good for humans to settle the Sahara desert and cross it to disperse out of Africa, versus times that would be inhospitable like today."

McGee and his colleagues have published their results today in Science Advances.

A puzzling pattern

Each year, winds from the northeast sweep up hundreds of millions of tons of Saharan dust, depositing much of this sediment into the Atlantic Ocean, off the coast of West Africa. Layers of this dust, built up over hundreds of thousands of years, can serve as a geologic chronicle of North Africa's climate history: Layers thick with dust may indicate arid periods, whereas those containing less dust may signal wetter eras.

Scientists have analyzed sediment cores dug up from the ocean bottom off the coast of West Africa, for clues to the Sahara's climate history. These cores contain layers of ancient sediment deposited over millions of years. Each layer can contain traces of Saharan dust as well as the remains of life forms, such as the tiny shells of plankton.

Past analyses of these sediment cores have unearthed a puzzling pattern: It would appear that the Sahara shifts between wet and dry periods every 100,000 years—a geologic beat that scientists have linked to the Earth's ice age cycles, which seem to also come and go every 100,000 years. Layers with a larger fraction of dust seem to coincide with periods when the Earth is covered in ice, whereas less dusty layers appear during interglacial periods, such as today, when ice has largely receded.

But McGee says this interpretation of the sediment cores chafes against climate models, which show that Saharan climate should be driven by the region's monsoon season, the strength of which is determined by the tilt of the Earth's axis and the amount of sunlight that can fuel monsoons in the summer.

"We were puzzled by the fact that this 20,000-year beat of local summer insolation seems like it should be the dominant thing controlling monsoon strength, and yet in dust records you see ice age cycles of 100,000 years," McGee says.

Beats in sync

To get to the bottom of this contradiction, the researchers used their own techniques to analyze a sediment core obtained off the coast of West Africa by colleagues from the University of Bordeaux—which was drilled only a few kilometers from cores in which others had previously identified a 100,000-year pattern.

The researchers, led by first author Charlotte Skonieczny, a former MIT postdoc and now a professor at Paris-Sud University, examined layers of sediment deposited over the last 240,000 years. They analyzed each layer for traces of dust and measured the concentrations of a rare isotope of thorium, to determine how rapidly dust was accumulating on the seafloor.

Thorium is produced at a constant rate in the ocean by very small amounts of radioactive uranium dissolved in seawater, and it quickly attaches itself to sinking sediments. As a result, scientists can use the concentration of thorium in the sediments to determine how quickly dust and other sediments were accumulating on the seafloor in the past: During times of slow accumulation, thorium is more concentrated, while at times of rapid accumulation, thorium is diluted. The pattern that emerged was very different from what others had found in the same sediment cores.

"What we found was that some of the peaks of dust in the cores were due to increases in dust deposition in the ocean, but other peaks were simply because of carbonate dissolution and the fact that during ice ages, in this region of the ocean, the ocean was more acidic and corrosive to calcium carbonate," McGee says. "It might look like there's more dust deposited in the ocean, when really, there isn't."

Once the researchers removed this confounding effect, they found that what emerged was primarily a new "beat," in which the Sahara vacillated between wet and dry climates every 20,000 years, in sync with the region's monsoon activity and the periodic tilting of the Earth.

"We can now produce a record that sees through the biases of these older records, and so doing, tells a different story," McGee says. "We've assumed that ice ages have been the key thing in making the Sahara dry versus wet. Now we show that it's primarily these cyclic changes in Earth's orbit that have driven wet versus dry periods. It seems like such an impenetrable, inhospitable landscape, and yet it's come and gone many times, and shifted between grasslands and a much wetter environment, and back to dry climates, even over the last quarter million years."

The point they were making, even then, was you can trigger an Ice Age by warming.

The bad winters they have had on occasion back East was caused by Arctic air coming down the Great Lakes, sucking up moisture, and dumping it along the coast.

- If the Arctic Ice starts clearing, opening up a larger expanse of water to Arctic air, then we are dead.

A year of snow in the Northern Latitudes, a year of rain in the Middle Latitudes will kill billions.

This has happened at least twice in the past 10k years, when the Sahara was green 10k and 6k years ago. What's interesting, is that National Geographic had the major article about the Green Sahara, yet now it is not listed on their site. I suspect people complained that it went against their bizarre religious beliefs about global warming. This is the original link that used to work.

When I've posted this stuff in the past, people always try to argue against without ever reading the information. I always ask:

- Didn't you ever wonder why the people in the North were still living in caves, while the major civilizations were booming in the Fertile Crescent. And why, when the people in the North were beginning to thrive, the Fertile Crescent turned to desert.

- Didn't you ever wonder how the Silk Road came to be. Did some guy load up his camel with silk, cross the trackless waste. When in reality, the whole region was well watered, fertile, and only over time were towns and cities abandoned as the region dried up.

This is not "Man Made" this is the Earth trying to kill us on a regular basis.

The key point in the study, as far as GET, is that the first group of people averaged six-five in height and the second group was five-six height, indicating that the Earth grew between the two populations.

I've been studying the expanding earth for a few years. My first introduction to it was a video produced by Neal Adams, which convinced me of the likelihood the earth's crust was growing. https://youtu.be/oJfBSc6e7QQNeal Adams - Science: 01 - Conspiracy: Earth is Growing!

Moments after watching that first video, I watched a second one about Europa that convinced me every body in the universe likely grew.https://youtu.be/zy3_sWF7tv4Neal Adams - Science: 05 - Conspiracy: Europa is Growing!

I did watch the remainder of the videos Adams made on the subject, but had a bit of problem with how he was trying to 'expand' the earth by growing molecules via Tachyons ... but I was in disagreement with his theory.

It was a few months later that I stumbled on part 1 of the video entitled "A Mechanism for Earth Expansion".

It provided the best explanation for how and why planets could become hollow. Researchers Peter Woodhead and Andrew Johnson speak in this two part series about evidence over the years that point to a hollow earth, including the gravity problem with dinosaurs.

They do answer most of my questions but bring up more. I wish they'd do a part 3 and expand on electric gravity (positive push from inside, as per Wal Thornhill) as a mechanism for expansion, which they touch briefly on their other videos.

There is much more evidence I've found, but this should be enough to give you food for thought.I've spent hours contemplating the ramifications if this is all true. It does answer many questions, why the moon rings like a bell, why the moon is moving away from the earth, why the day is getting longer, why Jupiter has a 'fuzzy' interior, etc.

Reading through the pdfs, watching the videos, I can see what is missing. He's talking about the "Expanding Earth", and the evidence shows a "Growing Earth", GET it. HA!

It's not "Growing or Expanding" it's "Growing" only. The term does control how you look at the evidence. That's why he was unable to accept the concept of new mass being generated. All of his work was to find a solution by dismissing new matter being made.

On page 10 of the first paper he says:

"I contend that Earth’s mass now is not significantly more than that pre-expansion."

"In simple terms, it is because the mass distribution beneath the surface of the Earth changes – which causes the centre of gravity in the heavier outer shell to move away from the centre of the Earth and get closer to the surface – as the non-gas layers get thinner."

Sorry, that violates physical laws. The gravity does not increase simply because most of the mass moves into the shell.

They did a study of the Earth's gravity map. They put a satellite in orbit that measured how its orbit moved up or down as it moved along its orbit. Think of driving along and there are dips and rises in the road. Each dip means more mass beneath it, each rise indicates less mass. The gravity is all of the Earth beneath that point. So if you have oceans below you on this side of the Earth, and oceans on the other side, there is less mass, less gravity, and the satellite will rise. If you have mountains below you on this side of the Earth and mountains on the other side, then there is more mass and the satellite will have more gravity at that point and will dip.

Growth is caused by transmutation from the base aether into hydrogen, and more complex atoms builds from there, all through transmutation. Hydrogen is simply a stable, concentrated form of aether, and can build more complex atoms.

Once you see transmutation as the source of growth, it's transmutation all the way down.

"Both Maxlow and Adams have suggested that our Earth’s mass has increased from the creation of new material within our planet. If that were true the mass of the Earth would have increased by a factor of 4.8, that has serious consequences for our relationship with the moon. By increasing Earth's mass by a factor of 4.8 would in turn increase the gravitational pull between ourselves and the moon. This would result in a decaying orbit and Earth's destruction."

The assumption through the whole paper is that the Solar System and the Earth have been around for billions of years. The Moon's orbit around the Earth is probably recent, not billions of years old. Orbits are too dynamic to be stable at such extreme time scales.

Then on the same page:

"Going back in time Earth's diameter would be progressively smaller, as a consequence Earth would have spun faster (the ice skater effect), creating a shorter day length and consequently many more days in a pre-Earth year."

Not necessarily. It has been shown that the Earth's rotation slows and speeds up due to major earthquakes, so there is no way to know what length the day was when the Earth was smaller.

Starting on page 3 of the second pdf his discussion of "Surface Gravity and Centre of Mass Force" shows where his theory falls apart. The second part didn't add to the discussion. He spent too much time responding to the very points I made above. HA!

Your post helps the thread grow, just like the Earth. Thanks for the links.

These clips from the PBS NewsHour for 30 January 2019, point to what I mentioned above. A warming can lead to extreme cold weather. This is a taste of what can happen if the Arctic Ice starts opening up more.

Hi allynh,Are you drawing a conclusion or making a prediction with regard to the current cold snap in the mid west? It is also cold here on the East coast, last night it was -3 degrees F here. Do you think this is a harbinger of an impending cooling or mini ice age?

I don not put much stock in this. As I have stated before imhop, the entire "global warming" debate is a contrived political issue with the underlying motivation to attack the prevailing economic system in the US and other Western nations. The changing of the politically correct nomenclature, with the replacement of the term "global warming" with "climate change", is nothing more than an attempt to insure that the movement will have validity regardless of how the climate changes. If it gets warmer or gets colder their position has validity and cannot be falsified. The fact is that weather is not static but is dynamic - it is always changing - so that proponents of that political agenda will have support for their position whatever the weather. This has plainly nothing to do with Science!

[Note: the above comment was only intended as a response to the link posted and not meant for discussion on this thread, which would be grossly off topic. There is at least one climate change/global warming thread on the Planetary Science board.]

HA! This has nothing to do with politics, this is science. Read the post a little bit up thread for the discussion scattered in the thread. One post leads to another. The first links start in 1958, long before people started playing games.